1 // SPDX-License-Identifier: GPL-2.0
5 * Copyright (C) 1991, 1992 Linus Torvalds
8 #include <linux/export.h>
10 #include <linux/errno.h>
11 #include <linux/file.h>
12 #include <linux/highuid.h>
14 #include <linux/namei.h>
15 #include <linux/security.h>
16 #include <linux/cred.h>
17 #include <linux/syscalls.h>
18 #include <linux/pagemap.h>
19 #include <linux/compat.h>
21 #include <linux/uaccess.h>
22 #include <asm/unistd.h>
25 * generic_fillattr - Fill in the basic attributes from the inode struct
26 * @inode: Inode to use as the source
27 * @stat: Where to fill in the attributes
29 * Fill in the basic attributes in the kstat structure from data that's to be
30 * found on the VFS inode structure. This is the default if no getattr inode
31 * operation is supplied.
33 void generic_fillattr(struct inode *inode, struct kstat *stat)
35 stat->dev = inode->i_sb->s_dev;
36 stat->ino = inode->i_ino;
37 stat->mode = inode->i_mode;
38 stat->nlink = inode->i_nlink;
39 stat->uid = inode->i_uid;
40 stat->gid = inode->i_gid;
41 stat->rdev = inode->i_rdev;
42 stat->size = i_size_read(inode);
43 stat->atime = inode->i_atime;
44 stat->mtime = inode->i_mtime;
45 stat->ctime = inode->i_ctime;
46 stat->blksize = i_blocksize(inode);
47 stat->blocks = inode->i_blocks;
49 EXPORT_SYMBOL(generic_fillattr);
52 * vfs_getattr_nosec - getattr without security checks
53 * @path: file to get attributes from
54 * @stat: structure to return attributes in
55 * @request_mask: STATX_xxx flags indicating what the caller wants
56 * @query_flags: Query mode (KSTAT_QUERY_FLAGS)
58 * Get attributes without calling security_inode_getattr.
60 * Currently the only caller other than vfs_getattr is internal to the
61 * filehandle lookup code, which uses only the inode number and returns no
62 * attributes to any user. Any other code probably wants vfs_getattr.
64 int vfs_getattr_nosec(const struct path *path, struct kstat *stat,
65 u32 request_mask, unsigned int query_flags)
67 struct inode *inode = d_backing_inode(path->dentry);
69 memset(stat, 0, sizeof(*stat));
70 stat->result_mask |= STATX_BASIC_STATS;
71 request_mask &= STATX_ALL;
72 query_flags &= KSTAT_QUERY_FLAGS;
74 /* allow the fs to override these if it really wants to */
75 if (IS_NOATIME(inode))
76 stat->result_mask &= ~STATX_ATIME;
77 if (IS_AUTOMOUNT(inode))
78 stat->attributes |= STATX_ATTR_AUTOMOUNT;
80 if (inode->i_op->getattr)
81 return inode->i_op->getattr(path, stat, request_mask,
84 generic_fillattr(inode, stat);
87 EXPORT_SYMBOL(vfs_getattr_nosec);
90 * vfs_getattr - Get the enhanced basic attributes of a file
91 * @path: The file of interest
92 * @stat: Where to return the statistics
93 * @request_mask: STATX_xxx flags indicating what the caller wants
94 * @query_flags: Query mode (KSTAT_QUERY_FLAGS)
96 * Ask the filesystem for a file's attributes. The caller must indicate in
97 * request_mask and query_flags to indicate what they want.
99 * If the file is remote, the filesystem can be forced to update the attributes
100 * from the backing store by passing AT_STATX_FORCE_SYNC in query_flags or can
101 * suppress the update by passing AT_STATX_DONT_SYNC.
103 * Bits must have been set in request_mask to indicate which attributes the
104 * caller wants retrieving. Any such attribute not requested may be returned
105 * anyway, but the value may be approximate, and, if remote, may not have been
106 * synchronised with the server.
108 * 0 will be returned on success, and a -ve error code if unsuccessful.
110 int vfs_getattr(const struct path *path, struct kstat *stat,
111 u32 request_mask, unsigned int query_flags)
115 retval = security_inode_getattr(path);
118 return vfs_getattr_nosec(path, stat, request_mask, query_flags);
120 EXPORT_SYMBOL(vfs_getattr);
123 * vfs_statx_fd - Get the enhanced basic attributes by file descriptor
124 * @fd: The file descriptor referring to the file of interest
125 * @stat: The result structure to fill in.
126 * @request_mask: STATX_xxx flags indicating what the caller wants
127 * @query_flags: Query mode (KSTAT_QUERY_FLAGS)
129 * This function is a wrapper around vfs_getattr(). The main difference is
130 * that it uses a file descriptor to determine the file location.
132 * 0 will be returned on success, and a -ve error code if unsuccessful.
134 int vfs_statx_fd(unsigned int fd, struct kstat *stat,
135 u32 request_mask, unsigned int query_flags)
140 if (query_flags & ~KSTAT_QUERY_FLAGS)
145 error = vfs_getattr(&f.file->f_path, stat,
146 request_mask, query_flags);
151 EXPORT_SYMBOL(vfs_statx_fd);
154 * vfs_statx - Get basic and extra attributes by filename
155 * @dfd: A file descriptor representing the base dir for a relative filename
156 * @filename: The name of the file of interest
157 * @flags: Flags to control the query
158 * @stat: The result structure to fill in.
159 * @request_mask: STATX_xxx flags indicating what the caller wants
161 * This function is a wrapper around vfs_getattr(). The main difference is
162 * that it uses a filename and base directory to determine the file location.
163 * Additionally, the use of AT_SYMLINK_NOFOLLOW in flags will prevent a symlink
164 * at the given name from being referenced.
166 * 0 will be returned on success, and a -ve error code if unsuccessful.
168 int vfs_statx(int dfd, const char __user *filename, int flags,
169 struct kstat *stat, u32 request_mask)
173 unsigned int lookup_flags = LOOKUP_FOLLOW | LOOKUP_AUTOMOUNT;
175 if ((flags & ~(AT_SYMLINK_NOFOLLOW | AT_NO_AUTOMOUNT |
176 AT_EMPTY_PATH | KSTAT_QUERY_FLAGS)) != 0)
179 if (flags & AT_SYMLINK_NOFOLLOW)
180 lookup_flags &= ~LOOKUP_FOLLOW;
181 if (flags & AT_NO_AUTOMOUNT)
182 lookup_flags &= ~LOOKUP_AUTOMOUNT;
183 if (flags & AT_EMPTY_PATH)
184 lookup_flags |= LOOKUP_EMPTY;
187 error = user_path_at(dfd, filename, lookup_flags, &path);
191 error = vfs_getattr(&path, stat, request_mask, flags);
193 if (retry_estale(error, lookup_flags)) {
194 lookup_flags |= LOOKUP_REVAL;
200 EXPORT_SYMBOL(vfs_statx);
203 #ifdef __ARCH_WANT_OLD_STAT
206 * For backward compatibility? Maybe this should be moved
207 * into arch/i386 instead?
209 static int cp_old_stat(struct kstat *stat, struct __old_kernel_stat __user * statbuf)
211 static int warncount = 5;
212 struct __old_kernel_stat tmp;
216 printk(KERN_WARNING "VFS: Warning: %s using old stat() call. Recompile your binary.\n",
218 } else if (warncount < 0) {
219 /* it's laughable, but... */
223 memset(&tmp, 0, sizeof(struct __old_kernel_stat));
224 tmp.st_dev = old_encode_dev(stat->dev);
225 tmp.st_ino = stat->ino;
226 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
228 tmp.st_mode = stat->mode;
229 tmp.st_nlink = stat->nlink;
230 if (tmp.st_nlink != stat->nlink)
232 SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
233 SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
234 tmp.st_rdev = old_encode_dev(stat->rdev);
235 #if BITS_PER_LONG == 32
236 if (stat->size > MAX_NON_LFS)
239 tmp.st_size = stat->size;
240 tmp.st_atime = stat->atime.tv_sec;
241 tmp.st_mtime = stat->mtime.tv_sec;
242 tmp.st_ctime = stat->ctime.tv_sec;
243 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
246 SYSCALL_DEFINE2(stat, const char __user *, filename,
247 struct __old_kernel_stat __user *, statbuf)
252 error = vfs_stat(filename, &stat);
256 return cp_old_stat(&stat, statbuf);
259 SYSCALL_DEFINE2(lstat, const char __user *, filename,
260 struct __old_kernel_stat __user *, statbuf)
265 error = vfs_lstat(filename, &stat);
269 return cp_old_stat(&stat, statbuf);
272 SYSCALL_DEFINE2(fstat, unsigned int, fd, struct __old_kernel_stat __user *, statbuf)
275 int error = vfs_fstat(fd, &stat);
278 error = cp_old_stat(&stat, statbuf);
283 #endif /* __ARCH_WANT_OLD_STAT */
285 #ifdef __ARCH_WANT_NEW_STAT
287 #if BITS_PER_LONG == 32
288 # define choose_32_64(a,b) a
290 # define choose_32_64(a,b) b
293 #ifndef INIT_STRUCT_STAT_PADDING
294 # define INIT_STRUCT_STAT_PADDING(st) memset(&st, 0, sizeof(st))
297 static int cp_new_stat(struct kstat *stat, struct stat __user *statbuf)
301 if (sizeof(tmp.st_dev) < 4 && !old_valid_dev(stat->dev))
303 if (sizeof(tmp.st_rdev) < 4 && !old_valid_dev(stat->rdev))
305 #if BITS_PER_LONG == 32
306 if (stat->size > MAX_NON_LFS)
310 INIT_STRUCT_STAT_PADDING(tmp);
311 tmp.st_dev = new_encode_dev(stat->dev);
312 tmp.st_ino = stat->ino;
313 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
315 tmp.st_mode = stat->mode;
316 tmp.st_nlink = stat->nlink;
317 if (tmp.st_nlink != stat->nlink)
319 SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
320 SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
321 tmp.st_rdev = new_encode_dev(stat->rdev);
322 tmp.st_size = stat->size;
323 tmp.st_atime = stat->atime.tv_sec;
324 tmp.st_mtime = stat->mtime.tv_sec;
325 tmp.st_ctime = stat->ctime.tv_sec;
326 #ifdef STAT_HAVE_NSEC
327 tmp.st_atime_nsec = stat->atime.tv_nsec;
328 tmp.st_mtime_nsec = stat->mtime.tv_nsec;
329 tmp.st_ctime_nsec = stat->ctime.tv_nsec;
331 tmp.st_blocks = stat->blocks;
332 tmp.st_blksize = stat->blksize;
333 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
336 SYSCALL_DEFINE2(newstat, const char __user *, filename,
337 struct stat __user *, statbuf)
340 int error = vfs_stat(filename, &stat);
344 return cp_new_stat(&stat, statbuf);
347 SYSCALL_DEFINE2(newlstat, const char __user *, filename,
348 struct stat __user *, statbuf)
353 error = vfs_lstat(filename, &stat);
357 return cp_new_stat(&stat, statbuf);
360 #if !defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_SYS_NEWFSTATAT)
361 SYSCALL_DEFINE4(newfstatat, int, dfd, const char __user *, filename,
362 struct stat __user *, statbuf, int, flag)
367 error = vfs_fstatat(dfd, filename, &stat, flag);
370 return cp_new_stat(&stat, statbuf);
374 SYSCALL_DEFINE2(newfstat, unsigned int, fd, struct stat __user *, statbuf)
377 int error = vfs_fstat(fd, &stat);
380 error = cp_new_stat(&stat, statbuf);
386 static int do_readlinkat(int dfd, const char __user *pathname,
387 char __user *buf, int bufsiz)
392 unsigned int lookup_flags = LOOKUP_EMPTY;
398 error = user_path_at_empty(dfd, pathname, lookup_flags, &path, &empty);
400 struct inode *inode = d_backing_inode(path.dentry);
402 error = empty ? -ENOENT : -EINVAL;
404 * AFS mountpoints allow readlink(2) but are not symlinks
406 if (d_is_symlink(path.dentry) || inode->i_op->readlink) {
407 error = security_inode_readlink(path.dentry);
410 error = vfs_readlink(path.dentry, buf, bufsiz);
414 if (retry_estale(error, lookup_flags)) {
415 lookup_flags |= LOOKUP_REVAL;
422 SYSCALL_DEFINE4(readlinkat, int, dfd, const char __user *, pathname,
423 char __user *, buf, int, bufsiz)
425 return do_readlinkat(dfd, pathname, buf, bufsiz);
428 SYSCALL_DEFINE3(readlink, const char __user *, path, char __user *, buf,
431 return do_readlinkat(AT_FDCWD, path, buf, bufsiz);
435 /* ---------- LFS-64 ----------- */
436 #if defined(__ARCH_WANT_STAT64) || defined(__ARCH_WANT_COMPAT_STAT64)
438 #ifndef INIT_STRUCT_STAT64_PADDING
439 # define INIT_STRUCT_STAT64_PADDING(st) memset(&st, 0, sizeof(st))
442 static long cp_new_stat64(struct kstat *stat, struct stat64 __user *statbuf)
446 INIT_STRUCT_STAT64_PADDING(tmp);
448 /* mips has weird padding, so we don't get 64 bits there */
449 tmp.st_dev = new_encode_dev(stat->dev);
450 tmp.st_rdev = new_encode_dev(stat->rdev);
452 tmp.st_dev = huge_encode_dev(stat->dev);
453 tmp.st_rdev = huge_encode_dev(stat->rdev);
455 tmp.st_ino = stat->ino;
456 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
458 #ifdef STAT64_HAS_BROKEN_ST_INO
459 tmp.__st_ino = stat->ino;
461 tmp.st_mode = stat->mode;
462 tmp.st_nlink = stat->nlink;
463 tmp.st_uid = from_kuid_munged(current_user_ns(), stat->uid);
464 tmp.st_gid = from_kgid_munged(current_user_ns(), stat->gid);
465 tmp.st_atime = stat->atime.tv_sec;
466 tmp.st_atime_nsec = stat->atime.tv_nsec;
467 tmp.st_mtime = stat->mtime.tv_sec;
468 tmp.st_mtime_nsec = stat->mtime.tv_nsec;
469 tmp.st_ctime = stat->ctime.tv_sec;
470 tmp.st_ctime_nsec = stat->ctime.tv_nsec;
471 tmp.st_size = stat->size;
472 tmp.st_blocks = stat->blocks;
473 tmp.st_blksize = stat->blksize;
474 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0;
477 SYSCALL_DEFINE2(stat64, const char __user *, filename,
478 struct stat64 __user *, statbuf)
481 int error = vfs_stat(filename, &stat);
484 error = cp_new_stat64(&stat, statbuf);
489 SYSCALL_DEFINE2(lstat64, const char __user *, filename,
490 struct stat64 __user *, statbuf)
493 int error = vfs_lstat(filename, &stat);
496 error = cp_new_stat64(&stat, statbuf);
501 SYSCALL_DEFINE2(fstat64, unsigned long, fd, struct stat64 __user *, statbuf)
504 int error = vfs_fstat(fd, &stat);
507 error = cp_new_stat64(&stat, statbuf);
512 SYSCALL_DEFINE4(fstatat64, int, dfd, const char __user *, filename,
513 struct stat64 __user *, statbuf, int, flag)
518 error = vfs_fstatat(dfd, filename, &stat, flag);
521 return cp_new_stat64(&stat, statbuf);
523 #endif /* __ARCH_WANT_STAT64 || __ARCH_WANT_COMPAT_STAT64 */
525 static noinline_for_stack int
526 cp_statx(const struct kstat *stat, struct statx __user *buffer)
530 memset(&tmp, 0, sizeof(tmp));
532 tmp.stx_mask = stat->result_mask;
533 tmp.stx_blksize = stat->blksize;
534 tmp.stx_attributes = stat->attributes;
535 tmp.stx_nlink = stat->nlink;
536 tmp.stx_uid = from_kuid_munged(current_user_ns(), stat->uid);
537 tmp.stx_gid = from_kgid_munged(current_user_ns(), stat->gid);
538 tmp.stx_mode = stat->mode;
539 tmp.stx_ino = stat->ino;
540 tmp.stx_size = stat->size;
541 tmp.stx_blocks = stat->blocks;
542 tmp.stx_attributes_mask = stat->attributes_mask;
543 tmp.stx_atime.tv_sec = stat->atime.tv_sec;
544 tmp.stx_atime.tv_nsec = stat->atime.tv_nsec;
545 tmp.stx_btime.tv_sec = stat->btime.tv_sec;
546 tmp.stx_btime.tv_nsec = stat->btime.tv_nsec;
547 tmp.stx_ctime.tv_sec = stat->ctime.tv_sec;
548 tmp.stx_ctime.tv_nsec = stat->ctime.tv_nsec;
549 tmp.stx_mtime.tv_sec = stat->mtime.tv_sec;
550 tmp.stx_mtime.tv_nsec = stat->mtime.tv_nsec;
551 tmp.stx_rdev_major = MAJOR(stat->rdev);
552 tmp.stx_rdev_minor = MINOR(stat->rdev);
553 tmp.stx_dev_major = MAJOR(stat->dev);
554 tmp.stx_dev_minor = MINOR(stat->dev);
556 return copy_to_user(buffer, &tmp, sizeof(tmp)) ? -EFAULT : 0;
560 * sys_statx - System call to get enhanced stats
561 * @dfd: Base directory to pathwalk from *or* fd to stat.
562 * @filename: File to stat or "" with AT_EMPTY_PATH
563 * @flags: AT_* flags to control pathwalk.
564 * @mask: Parts of statx struct actually required.
565 * @buffer: Result buffer.
567 * Note that fstat() can be emulated by setting dfd to the fd of interest,
568 * supplying "" as the filename and setting AT_EMPTY_PATH in the flags.
570 SYSCALL_DEFINE5(statx,
571 int, dfd, const char __user *, filename, unsigned, flags,
573 struct statx __user *, buffer)
578 if (mask & STATX__RESERVED)
580 if ((flags & AT_STATX_SYNC_TYPE) == AT_STATX_SYNC_TYPE)
583 error = vfs_statx(dfd, filename, flags, &stat, mask);
587 return cp_statx(&stat, buffer);
591 static int cp_compat_stat(struct kstat *stat, struct compat_stat __user *ubuf)
593 struct compat_stat tmp;
595 if (sizeof(tmp.st_dev) < 4 && !old_valid_dev(stat->dev))
597 if (sizeof(tmp.st_rdev) < 4 && !old_valid_dev(stat->rdev))
600 memset(&tmp, 0, sizeof(tmp));
601 tmp.st_dev = new_encode_dev(stat->dev);
602 tmp.st_ino = stat->ino;
603 if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
605 tmp.st_mode = stat->mode;
606 tmp.st_nlink = stat->nlink;
607 if (tmp.st_nlink != stat->nlink)
609 SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
610 SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
611 tmp.st_rdev = new_encode_dev(stat->rdev);
612 if ((u64) stat->size > MAX_NON_LFS)
614 tmp.st_size = stat->size;
615 tmp.st_atime = stat->atime.tv_sec;
616 tmp.st_atime_nsec = stat->atime.tv_nsec;
617 tmp.st_mtime = stat->mtime.tv_sec;
618 tmp.st_mtime_nsec = stat->mtime.tv_nsec;
619 tmp.st_ctime = stat->ctime.tv_sec;
620 tmp.st_ctime_nsec = stat->ctime.tv_nsec;
621 tmp.st_blocks = stat->blocks;
622 tmp.st_blksize = stat->blksize;
623 return copy_to_user(ubuf, &tmp, sizeof(tmp)) ? -EFAULT : 0;
626 COMPAT_SYSCALL_DEFINE2(newstat, const char __user *, filename,
627 struct compat_stat __user *, statbuf)
632 error = vfs_stat(filename, &stat);
635 return cp_compat_stat(&stat, statbuf);
638 COMPAT_SYSCALL_DEFINE2(newlstat, const char __user *, filename,
639 struct compat_stat __user *, statbuf)
644 error = vfs_lstat(filename, &stat);
647 return cp_compat_stat(&stat, statbuf);
650 #ifndef __ARCH_WANT_STAT64
651 COMPAT_SYSCALL_DEFINE4(newfstatat, unsigned int, dfd,
652 const char __user *, filename,
653 struct compat_stat __user *, statbuf, int, flag)
658 error = vfs_fstatat(dfd, filename, &stat, flag);
661 return cp_compat_stat(&stat, statbuf);
665 COMPAT_SYSCALL_DEFINE2(newfstat, unsigned int, fd,
666 struct compat_stat __user *, statbuf)
669 int error = vfs_fstat(fd, &stat);
672 error = cp_compat_stat(&stat, statbuf);
677 /* Caller is here responsible for sufficient locking (ie. inode->i_lock) */
678 void __inode_add_bytes(struct inode *inode, loff_t bytes)
680 inode->i_blocks += bytes >> 9;
682 inode->i_bytes += bytes;
683 if (inode->i_bytes >= 512) {
685 inode->i_bytes -= 512;
688 EXPORT_SYMBOL(__inode_add_bytes);
690 void inode_add_bytes(struct inode *inode, loff_t bytes)
692 spin_lock(&inode->i_lock);
693 __inode_add_bytes(inode, bytes);
694 spin_unlock(&inode->i_lock);
697 EXPORT_SYMBOL(inode_add_bytes);
699 void __inode_sub_bytes(struct inode *inode, loff_t bytes)
701 inode->i_blocks -= bytes >> 9;
703 if (inode->i_bytes < bytes) {
705 inode->i_bytes += 512;
707 inode->i_bytes -= bytes;
710 EXPORT_SYMBOL(__inode_sub_bytes);
712 void inode_sub_bytes(struct inode *inode, loff_t bytes)
714 spin_lock(&inode->i_lock);
715 __inode_sub_bytes(inode, bytes);
716 spin_unlock(&inode->i_lock);
719 EXPORT_SYMBOL(inode_sub_bytes);
721 loff_t inode_get_bytes(struct inode *inode)
725 spin_lock(&inode->i_lock);
726 ret = __inode_get_bytes(inode);
727 spin_unlock(&inode->i_lock);
731 EXPORT_SYMBOL(inode_get_bytes);
733 void inode_set_bytes(struct inode *inode, loff_t bytes)
735 /* Caller is here responsible for sufficient locking
736 * (ie. inode->i_lock) */
737 inode->i_blocks = bytes >> 9;
738 inode->i_bytes = bytes & 511;
741 EXPORT_SYMBOL(inode_set_bytes);